The development of alternative energy sources that reduce the.current dependence on fossil fuels will dramatically improve public health in urban environments by reducing pollution levels. Sunlight is an abundant energy source, but its use requires conversion to another form of energy. Using light to "split" water into molecular hydrogen and oxygen is an especially attractive energy conversion because hydrogen is a pollution-free fuel. Effecting this conversion requires a catalyst that can accumulate multiple one- electron oxidations and undergo two-electron reductions coupled to bond formation between oxygen atoms derived from water. The proposed research describes a design for such a catalyst based on a hypothesized oxygen-oxygen bond formation between an aroyloxyl radical and an oxoiron(IV) porphyrin. A small collection of catalysts that enable the generation of an aroyloxyl radical in the vicinity of an oxoiron(IV) porphyrin will be synthesized. Initial studies will evaluate these catalysts for their ability to form a peroxycarboxylate iron(lll) porphyrin via intramolecular oxygen-oxygen bond formation. Subsequently, the catalysts will be evaluated for the production of molecular oxygen from water.